African nations have taken the biggest steps in reducing corruption over the past 10 years, the World Bank has said.

A report measuring the quality of government in 212 countries from 1996 to 2006 found Africa had shown the greatest improvement.

The report judged whether countries had free media, political stability, the rule of law and control of corruption.

Countries in decline included Zimbabwe and Venezuela, but there were as many gainers as losers.

Critical for growth

Legitimate and effective political authority in managing society's affairs is crucial to eliminating poverty and lifting the standards of living of the citizens in a country, the report concluded.

"Such improvements in governance are critical for aid effectiveness and for sustained long-run growth," said Daniel Kaufmann, co-author of the report and director of global programmes at the World Bank.

ON THE RISE

Angola

Algeria

Sierra Leone

Latvia

"Bribery around the world is estimated at about $1 trillion (£494bn) and the burden of corruption falls disproportionately on the bottom billion people living in extreme poverty," he continued.

The bank's Governance Matters, 2007: Worldwide Governance Indicators 1996-2006 study highlighted the number of African countries that had made great strides in improving various aspects of government.

Kenya, Niger and Sierra Leone, the latter suffering a decade of civil war until 2002, were picked out for marked improvements in allowing their people the right to choose their government and freedom of expression, which includes an unconstrained press.

Angola, Rwanda and Sierra Leone were also acknowledged for their enhanced political stability.

Little overall improvement

The report noted the fast-paced progress of emerging economies, including Estonia, Latvia, the Czech Republic and Costa Rica, which score higher on key dimensions of governance than their industrialised counterparts, including Greece and Italy.

ON THE DECLINE

Zimbabwe

Ivory Coast

Belarus

Venezuela

But on the whole, the bank said there had been little improvement to the quality of government around the world over the past decade.

Shlomo Yitzhaki, director of Israel's Central Bureau of Statistics and Professor of Economics at Hebrew University, said the World Bank's governance indicators were a "crucial tool" for policy analysts and decision-makers benchmarking their countries.

"It definitely sets a standard for transparency in data," he added.

Good governance has increasingly become a key factor in granting aid to developing countries, and was a policy closely associated with World Bank head Paul Wolfowitz, who was forced to resign last month.